Please join me in an ode to the giant tortoise, recently confirmed to be back from near extinction on the Galapagos Espanola Island after conservation work that began forty years ago. The population currently stands at over 1000, a spectacular recovery considering that only 15 remained in the late 1960s, when they were summarily rounded up and placed into a breeding program. There are now enough adults and juveniles surviving and repopulating to be self-sustaining.

Although one can never say ‘giant tortoise’ enough times, the island still requires some habitat restoration. The tortoises should be able to help that along, because in addition to being long-lived, they are also superb ecosystem engineers. They disperse seeds and other organisms, stimulate recruitment of cactus trees (one of their primary food sources) by distributing pods as they eat, and also, under the right conditions, control woody plant growth, which helps maintain habitat for an endangered albatross that also nests on the island. One could almost call them “masters of the (island) house”. Whoever thought this waddly wild wonk would be a model for humans to improve environment through adept household behaviour?

If society is Espanola Island – in need of some major restructuring to achieve ecological health – then the tortoises are the epitome of small, incremental change-makers that eventually create a paradigm shift. Their localised, small-scale influences – grazing on cacti and spreading seeds in their home range – eventually combine to shift the entire ecosystem towards its natural equilibrium.

But the tortoises could not, and cannot, do it all on their own. Sound like a familiar cry? The population decline was not simply due to natural causes: feral goats introduced in the late 1800s chewed their way through the island’s vegetation, destroying the cacti and causing an explosion of woody plants, which further inhibited cactus regrowth – a disastrous combination for the tortoises. (This is of course a prime example of the dangers of invasive species. The next time border control stops you in case there are fruit flies in your cut mango, don’t complain!) The breeding program thus had to be paired with a concerted goat eradication effort, which itself took around 20 years. Even with population viability, a good deal more effort needs to be put into removing woody plants before the tortoises can be fully effective as ecosystem engineers.

So, although the tortoises are powerfully influential in the aggregate, even they need a helping hand – or in other words, when the system has been flipped into a state unconducive to change, small-scale efforts can only take you so far. As found in a recent OECD study, greener household behaviour can combine to create major reductions in waste, as well as water and energy use. These actions may even form the vanguard of a wider societal transition, but these incremental moves are sometimes overpowered by larger structural failings. Moreover, evidence suggests that even when individuals are open to pro-environmental actions, including lifestyle sacrifices, they may not follow through due to societal pressures or perceived time, effort, and cost constraints – but they may accept political changes that will externally drive this behaviour.

Thus, for issues requiring large-scale reorganisation such as the energy or food supply systems, it is essential to create an enabling environment for society’s members to achieve their full potential. Taking a cue from Espanola Island, policy-makers may do well to foster top-down change, or barring that, to eradicate some of the “goats”. (No goats were harmed in the writing of this piece. The author would also like to clarify that she loves goats.)